CN106517720A - Sewage sludge multi-stage coupling plate-and-frame filter-pressing dewatering device based on multi-point sludge feeding and use method of device - Google Patents

Abstract

A multi-stage coupled plate-frame filter press dewatering device for sewage sludge based on multi-point mud feeding and a use method thereof, relating to a plate-frame filter press dewaterer and a use method thereof. The invention aims to solve the technical problem of low dewatering efficiency of the current plate and frame filter press. The present invention is made up of main mud inlet pipe, mud inlet branch pipe, plate and frame filter press, screw conveyor, mixing breaker, quicklime dosing pipe, and secondary filter press mud inlet pipe; the filter plate of the plate and frame filter press has 5 mud inlet holes; the screw conveyor is located under the plate-and-frame filter press and communicates with the mixing crusher, the secondary pressure filter inlet pipe is respectively connected with the mixing crusher and mud inlet main pipe, and the quicklime dosing pipe is connected with the mixing crusher connected. The use method of this device: the first stage of pressure filtration, mixing and crushing, and the second stage of pressure filtration. The invention reduces the water content of the sludge to less than 60%, the water content difference in the plane direction of the mud cake can be reduced to less than 0.2%, and the water content difference in the longitudinal direction of the mud cake can be reduced to less than 1%.

Description

A multi-stage coupling plate and frame filter press dehydration device for sewage sludge based on multi-point mud entry and its how to use it

technical field

The invention relates to a plate and frame filter press dehydration device and a using method thereof.

Background technique

At present, there are about 3,000 sewage treatment plants in operation in China, and the designed daily treatment capacity is about 1.33×10 ⁸ m ³ /d. Excess sludge is a by-product of sewage treatment, and the amount of wet sludge generally accounts for about 0.3%-0.5% of the total volume of sewage. With the economic growth of our country, the amount of sewage treatment is increasing day by day, and the output of surplus sludge is increasing rapidly, reaching 230-300 million tons in 2010 and 250-350 million tons in 2011, with an annual growth rate of more than 10%. Surplus sludge has the characteristics of complex components, high moisture content, large volume, unstable properties, easy to rot and produce odor, etc. If it is not properly disposed of, it will easily cause secondary pollution to soil, water and air. Statistics show that the cost of sludge treatment and disposal in my country exceeds 30% of the total operating cost of sewage plants. The treatment and disposal of excess sludge has become an urgent problem to be solved. The "National Medium and Long-Term Science and Technology Development Program (2006-2020)" clearly points out that it is necessary to vigorously strengthen sludge reduction, resource utilization and safe disposal.

At present, the final disposal methods of sludge mainly include sanitary landfill, land use, sludge composting and sludge incineration, etc. However, no matter what kind of sludge disposal method, the sludge should be dehydrated first to reduce the moisture content of the sludge . The moisture content of the remaining sludge is generally 97% to 99%, including interstitial water, capillary (bound) water, adsorption water and internal water. Sludge with a relatively high water content is in the form of flowing liquid, which is not conducive to transportation and disposal. When the moisture content of the sludge is reduced from 97% to 99% to 94% to 96%, its volume can be reduced to 1/4 of its original size. When the moisture content of the sludge is 80%, the landfill area is about 3.2 times that of the sludge with a moisture content of 50%. The dehydration and volume reduction of sludge is the most important link in sludge treatment and disposal. High-efficiency dehydration will greatly reduce the moisture content of sludge and reduce the volume of sludge. It is of great significance to occupy landfill and prolong its service life, increase the calorific value of sludge incineration, reduce the cost of sludge post-treatment and disposal, and provide favorable conditions for further resource treatment.

At present, the sludge dewatering process mainly adopts the method of dehydration after primary conditioning. According to the different properties of sludge and dehydration methods, the moisture content of sludge after dehydration fluctuates greatly. At present, mechanical dehydration is the most widely used dehydration method in my country. Commonly used mechanical dehydration methods are belt filter press dehydration and plate and frame filter press dehydration. They mainly remove free water in sludge, and the energy consumption is high. After dehydration, the mud cake Most of the water content is 70% to 80%, and the mud cake still has certain flow characteristics, and its subsequent disposal is still difficult and costly. In recent years, there have been some improved plate and frame filter press dehydration methods that can reduce the moisture content of sludge to 60% to 70%, but most of them are at the cost of increasing dehydration energy consumption. If it is necessary to further remove moisture, it needs to be dried, incinerated, etc., and the energy consumption is relatively high. Moreover, reducing the moisture content of dewatered sludge by increasing energy input not only consumes too much energy, but also puts forward higher strength requirements for equipment, resulting in greater energy loss, material waste, and higher processing costs. However, the common final disposal methods of sludge need to treat the sludge to a water content below 60%. However, the document Huanban [2010] No. "Notice" also clearly stated: "Where sewage treatment plants transport sludge to the factory for the purpose of storage (that is, no treatment and disposal), the sludge must be dehydrated to a moisture content of less than 50%." When the moisture content of the sludge is between 60% and 65%, it is viscous, and the water molecules are wrapped by a layer of colloid. This area is called the "viscose phase area" of the sludge, and it is the area with the greatest resistance to sludge dehydration. At present, the sludge dehydration technology and equipment are difficult to meet the higher environmental requirements of our country. However, domestic and foreign researches on the dehydration process parameter mechanism, control, water distribution and mutual transformation law, dewatering cake microstructure change law and corresponding mechanism of action, etc. Insufficient, which limits the improvement of sludge dewatering efficiency. Therefore, how to effectively improve the efficiency of sludge dewatering within the scope of existing equipment conditions and energy consumption has become a key issue for sludge reduction, harmlessness and resource utilization, which has great practical significance for improving the environment.

At present, the plate and frame filter press used in the sludge dewatering process of the sewage treatment plant mostly has uneven water content distribution in the plane direction and the longitudinal direction of the mud cake after filtration. During the plate and frame filter press process of sludge, the outer layer of the mud cake has a higher dehydration efficiency and is easy to be compressed, while the center layer of the mud cake has a lower dehydration efficiency and lags behind that of the outer layer. With the progress of the filter press process, when the moisture content of the outer layer of the mud cake is lower than a certain level, the outer layer of the mud cake will appear hardened, which will hinder the removal of water in the middle layer of the mud cake, and the required time for further removal of water in the mud cake The pressure increased greatly, resulting in a high moisture content in the center layer of the mud cake, making it difficult to remove the moisture. At the same time, most of the current plate and frame filter presses enter the mud at a single point, and there is also an uneven distribution of moisture content in the direction of the mud cake plane, and there are differences in the moisture content of the mud cake at different distances from the mud entry point. All of the above phenomena will cause uneven mass transfer in filter press dehydration, which greatly limits the improvement of dehydration efficiency.

Contents of the invention

The present invention aims to solve the technical problems of uneven water content distribution and low dehydration efficiency in the plane direction and longitudinal direction of the mud cake after plate and frame filter press, and provides a kind of sewage sludge based on multi-point mud feeding. A multi-stage coupling plate and frame filter press dehydration device and a use method thereof.

The sewage sludge multi-stage coupling plate and frame filter press dewatering device based on multi-point mud feeding of the present invention is composed of a first-stage filter press mud inlet valve 1, a mud inlet main pipe 2, a mud inlet branch pipe 3, a plate and frame filter press 4, and a screw filter press. Conveyor 5, mixing breaker 6, quicklime dosing pipe 7, plunger pump or solid pump 8, secondary pressure filter inlet pipe 9, secondary pressure filter inlet valve 10 and mud inlet pump 12; The mud inlet branch pipe 3 is composed of 5 pipes, and the 5 pipes are arranged parallel to each other. The cross-sectional positions of the four pipes form the four vertices of a square, and the cross-section of the remaining pipe is located at the geometric center of the square; the plate frame The filter plate of the filter press 4 is a square with five mud inlet holes 11, one of which is located at the geometric center point of the filter plate, and the other four mud inlet holes 11 are located at the four vertices and the geometric center of the filter plate. The middle point of the connecting line; the 5 pipes of the mud inlet branch pipe 3 correspond to the positions of the 5 mud inlet holes 11 on the filter plate of the plate and frame filter press 4;

The mud inlet pump 12 is connected to one end of the mud inlet valve 1 of the first-stage filter press, the other end of the mud inlet valve 1 of the first-stage filter press is connected to the mud inlet main pipe 2, and the other end of the mud inlet main pipe 2 is connected to the 5 ends of the mud inlet branch pipe 3 respectively. The root canals are connected, and the other ends of the five pipes of the mud inlet branch pipe 3 communicate with the five mud inlet holes 11 on the filter plate of the plate and frame filter press 4 one by one. The screw conveyor 5 is located at the bottom of the plate and frame filter press 4 Directly below, the discharge port of the screw conveyor 5 is connected with the feed port of the mixing crusher 6, and the discharge port of the mixing crusher 6 is connected with the mud inlet pipe 9 of the secondary filter press, and the mud inlet pipe 9 of the secondary filter press The other end is connected to a secondary pressure filter mud inlet valve 10, and the other end of the secondary pressure filter mud inlet valve 10 is connected to the mud inlet main pipe 2 between the primary filter pressure mud inlet valve 1 and the mud inlet branch pipe 3. A plunger pump or a solid pump 8 is arranged on the mud inlet pipe 9 of the filter press, and the medicine outlet of the quicklime dosing pipe 7 communicates with the medicine inlet of the mixing crusher 6 .

The method of using the sewage sludge multi-stage coupling plate and frame filter press dehydration device based on multi-point mud feeding of the present invention is as follows:

1. First-stage filter press: open the first-stage filter press mud inlet valve 1, close the second-stage filter press mud inlet valve 10, start the mud inlet pump 12, and pass the sludge to be treated through the mud inlet main pipe 2 in sequence under low pressure conditions , five mud inlet holes 11 on the filter plate of the mud inlet branch pipe 3 and the plate and frame filter press 4 are transported into the plate and frame filter press 4, and when the sludge stops entering the plate and frame filter press 4, the mud inlet pump is raised 12 pressure, the sludge to be treated will continue to be transported into the plate and frame filter press 4 for dehydration under high pressure conditions. Pump 12, and then carry out tympanic membrane pressure filtration to the diaphragm plate in the filter plate of plate-and-frame filter press 4, stop the tympanic membrane pressure filtration when the mud cake formed after the pressure filtration is hardened, and complete the first stage of pressure filtration;

The low pressure condition is that the mud inlet pressure is 0.4MPa～0.8MPa; the high pressure condition is that the mud inlet pressure is 1.0MPa～1.4MPa; the pressure of the tympanic membrane filter is 1.2MPa～1.6MPa;

2. Mixing and crushing: After the first stage of pressure filtration, the plate and frame filter press 4 is opened, and the mud cake formed after the pressure filtration falls into the screw conveyor 5, and is transported to the mixing crusher 6, and the quicklime is fed through the quicklime The drug pipe 7 is added to the mixing crusher 6 and mixed with the mud cake until the plunger pump or the solid pump 8 can make the mixed and crushed sludge enter the mud pipe 9 of the secondary pressure filter; the dosage of quicklime 0.01g/gSS～0.05g/gSS;

3. Second-stage filter press: Open the second-stage filter press mud inlet valve 10 and the plunger pump or solid pump 8, and the sludge mixed and crushed by the mixing crusher 6 passes through the second-stage filter press mud inlet pipe 9 and mud inlet in turn. The main pipe 2, the mud inlet branch pipe 3 and the five mud inlet holes 11 on the filter plate of the plate and frame filter press 4 are transported into the plate and frame filter press 4, and when the sludge stops entering the plate and frame filter press 4, close Second stage filter press mud inlet valve 10 and plunger pump or solid pump 8, and then perform tympanic membrane pressure filtration on the diaphragm plate in the filter plate of plate and frame filter press 4 until the plate and frame filter press 4 stops draining. Press filtration, use dry gas or hot gas to blow back the mud cake in the plate and frame filter press 4 for 5 minutes to remove the moisture on the surface of the mud cake, that is to complete the dehydration process; the pressure of the tympanic filter press is 1.6MPa-2.0MPa.

The compaction phenomenon of the mud cake formed after the press filtration refers to the state when the water content of the mud cake is 80% to 90%.

In the present invention, in the first-stage filter press, the way of multi-point mud feeding can make the mud feeding in the plate and frame filter press more uniform in the low-pressure mud feeding stage, and improve the mud feeding amount and mud feeding effect; multi-point mud feeding The method can improve the uniformity of mud feeding and filtration in the stage of high-pressure mud feeding and pressure filtration, reduce the phenomenon of uneven distribution and mass transfer of pressure and filtration in the plane direction of mud cake, and then improve the effect of filtration;

In the present invention, the method of multi-point mud feeding can make the mud feeding in the plate-and-frame filter press more uniform and smooth during the second-stage filter press mud feeding process, reduce the possibility of mud feeding blockage, and increase the amount of mud feeding and Into the mud effect.

The invention improves the mass transfer efficiency of the dehydration in the plane direction of the mud cake through the way of multi-point mud feeding, and reduces the uneven distribution of the water content of the mud cake in the plane direction; In the initial stage of the hardening phenomenon, the mud cake is crushed, and after mixing, it is dehydrated by secondary mechanical extrusion, so as to avoid the limitation of the outer layer of the mud cake on the mass transfer efficiency of dehydration in the longitudinal direction, and reduce the moisture content of the mud cake The uneven distribution of moisture content in the longitudinal direction; the method of the present invention is expected to improve the sludge dehydration efficiency, reduce dehydration pressure and time, and further reduce dehydration energy consumption and cost.

The dosage of quicklime in step 2 is 0.01g/gSS-0.05g/gSS, which means adding 0.01g-0.05g of quicklime per gram of dry sludge.

The effect of unslaked lime of the present invention is as follows:

1. Calcium ions in quicklime serve as the skeleton structure of sludge to improve the morphology and structure of sludge flocs and improve their compression resistance;

2. As a desiccant;

3. Alkaline conditions destroy sludge extracellular polymers and release bound water.

Advantages of the present invention:

(1) The present invention can effectively reduce the water content of the mud cake after the press filtration and reduce the energy consumption (pressure and time) of the press filter, has a good sludge dehydration effect, and can reduce the water content of the sludge from 97% to 98% to 60% % or less, under the same energy consumption conditions, the moisture content of the mud cake after pressing can be reduced by 3% to 10%;

(2) The present invention is simple in operation and convenient in operation. Compared with the existing plate and frame filter press method, there is no need to increase large-scale equipment, and no need to replace existing equipment. It can be modified and upgraded on the basis of the existing plate and frame filter press. The transformation cost is low, and it is easy to be widely used in sewage treatment plants;

(3) The present invention can effectively reduce the uneven distribution of water content of the mud cake after press filtration, and the water content difference at different positions in the plane direction of the mud cake can be reduced to below 0.2%. Cake outer layer) the difference in moisture content at different positions can be reduced to less than 1%.

Description of drawings

Fig. 1 is a schematic diagram of a multi-stage coupling plate and frame filter press dehydration device for sewage sludge based on multi-point mud feeding in Embodiment 1;

Fig. 2 is the cross-sectional view of the filter plate of the plate and frame filter press 4 in the specific embodiment one;

Fig. 3 is a sectional view along the a-a direction of the mud inlet branch pipe 3 in Fig. 1 .

detailed description

Specific implementation mode 1: see Figures 1, 2 and 3. This implementation mode is a multi-stage coupling plate and frame filter press dehydration device for sewage sludge based on multi-point mud entry, specifically consisting of a first-stage filter press mud intake valve 1, Mud inlet main pipe 2, mud inlet branch pipe 3, plate and frame filter press 4, screw conveyor 5, mixing crusher 6, quicklime dosing pipe 7, plunger pump or solid pump 8, secondary pressure filter inlet mud pipe 9, The secondary pressure filter mud inlet valve 10 and the mud inlet pump 12 are composed; the mud inlet branch pipe 3 is composed of 5 pipes, and the 5 pipes are arranged parallel to each other, and the cross-sectional positions of the 4 pipes form four vertices of a square. The section of the remaining pipe is located at the geometric center of the square; the filter plate of the plate-and-frame filter press 4 is a square with five mud inlet holes 11, one of which is located at the geometric center of the filter plate , and the other four mud inlet holes 11 are located at the middle points of the four vertices of the filter plate and the geometric center point; The positions of the mud inlet holes 11 are in one-to-one correspondence;

The mud inlet pump 12 is connected to one end of the mud inlet valve 1 of the first-stage filter press, the other end of the mud inlet valve 1 of the first-stage filter press is connected to the mud inlet main pipe 2, and the other end of the mud inlet main pipe 2 is connected to the 5 ends of the mud inlet branch pipe 3 respectively. The root canals are connected, and the other ends of the five pipes of the mud inlet branch pipe 3 communicate with the five mud inlet holes 11 on the filter plate of the plate and frame filter press 4 one by one. The screw conveyor 5 is located at the bottom of the plate and frame filter press 4 Directly below, the discharge port of the screw conveyor 5 is connected with the feed port of the mixing crusher 6, and the discharge port of the mixing crusher 6 is connected with the mud inlet pipe 9 of the secondary filter press, and the mud inlet pipe 9 of the secondary filter press The other end is connected to a secondary pressure filter mud inlet valve 10, and the other end of the secondary pressure filter mud inlet valve 10 is connected to the mud inlet main pipe 2 between the primary filter pressure mud inlet valve 1 and the mud inlet branch pipe 3. A plunger pump or a solid pump 8 is arranged on the mud inlet pipe 9 of the filter press, and the medicine outlet of the quicklime dosing pipe 7 communicates with the medicine inlet of the mixing crusher 6 .

Embodiment 2: This embodiment is the method of using the sewage sludge multi-stage coupling plate and frame filter press dewatering device based on multi-point mud feeding in Embodiment 1, see Figures 1, 2 and 3, and the specific steps are as follows:

1. First-stage filter press: open the first-stage filter press mud inlet valve 1, close the second-stage filter press mud inlet valve 10, start the mud inlet pump 12, and pass the sludge to be treated through the mud inlet main pipe 2 in sequence under low pressure conditions , five mud inlet holes 11 on the filter plate of the mud inlet branch pipe 3 and the plate and frame filter press 4 are transported into the plate and frame filter press 4, and when the sludge stops entering the plate and frame filter press 4, the mud inlet pump is raised 12 pressure, the sludge to be treated will continue to be transported into the plate and frame filter press 4 for dehydration under high pressure conditions. Pump 12, and then perform tympanic membrane pressure filtration on the diaphragm plate in the filter plate of the plate and frame filter press 4, stop the tympanic membrane pressure filtration when the mud cake formed after the pressure filtration is compacted, and complete the first stage of pressure filtration. The moisture content of the mud cake after the first-stage filter press is 80% to 90%;

The low pressure condition is that the mud inlet pressure is 0.4MPa～0.8MPa; the high pressure condition is that the mud inlet pressure is 1.0MPa～1.4MPa; the pressure of the tympanic membrane filter is 1.2MPa～1.6MPa;

2. Mixing and crushing: After the first stage of pressure filtration, the plate and frame filter press 4 is opened, and the mud cake formed after the pressure filtration falls into the screw conveyor 5, and is transported to the mixing crusher 6, and the quicklime is fed through the quicklime The drug pipe 7 is added to the mixing crusher 6 and mixed with the mud cake until the plunger pump or the solid pump 8 can make the mixed and crushed sludge enter the mud pipe 9 of the secondary pressure filter; the dosage of quicklime 0.01g/gSS～0.05g/gSS;

3. Second-stage filter press: Open the second-stage filter press mud inlet valve 10 and the plunger pump or solid pump 8, and the sludge mixed and crushed by the mixing crusher 6 passes through the second-stage filter press mud inlet pipe 9 and mud inlet in turn. The main pipe 2, the mud inlet branch pipe 3 and the five mud inlet holes 11 on the filter plate of the plate and frame filter press 4 are transported into the plate and frame filter press 4, and when the sludge stops entering the plate and frame filter press 4, close Second stage filter press mud inlet valve 10 and plunger pump or solid pump 8, and then perform tympanic membrane pressure filtration on the diaphragm plate in the filter plate of plate and frame filter press 4 until the plate and frame filter press 4 stops draining. Press filtration, use dry gas or hot gas to blow back the mud cake in the plate and frame filter press 4 for 5 minutes to remove the moisture on the surface of the mud cake, that is to complete the dehydration process; the pressure of the tympanic filter press is 1.6MPa-2.0MPa.

Embodiment 3: The difference between this embodiment and Embodiment 1 is that the crushing method of the mixing crusher 6 is stirring or impacting. Others are the same as the first embodiment.

Embodiment 4: The difference between this embodiment and Embodiment 1 is that the filter plate includes a diaphragm plate, a matching plate and an anti-corrosion plate. Others are the same as the first embodiment.

Embodiment 5: The difference between this embodiment and Embodiment 2 is that the blowing described in step 1 is completed by a blower or an air compressor. Others are the same as in the second embodiment.

Embodiment 6: The difference between this embodiment and Embodiment 2 is that the air blowing described in Step 3 is completed by a blower or an air compressor. Others are the same as in the second embodiment.

Embodiment 7: The difference between this embodiment and Embodiment 2 is that the gas in the dry gas or hot gas in Step 3 is air, carbon dioxide or nitrogen. Others are the same as in the second embodiment.

Embodiment eight: the difference between this embodiment and embodiment one is: the area of 5 mud inlet holes 11 is less than or equal to 20% of the area of the mud inlet hole 11 in the filter plate of the plate and frame filter press 4 , and greater than or equal to 5% of the area of the surface where the mud inlet hole 11 is located in the filter plate of the plate and frame filter press 4 . Others are the same as the first embodiment.

Prove the beneficial effect of the present invention by following test:

Test 1: See Figures 1, 2 and 3. This test is a multi-stage coupling plate and frame filter press dehydration device for sewage sludge based on multi-point mud feeding. Specifically, it consists of a first-stage filter press mud inlet valve 1, mud inlet main pipe 2. Mud inlet branch pipe 3. Plate and frame filter press 4. Screw conveyor 5. Mixing crusher 6. Quicklime dosing pipe 7. Plunger pump or solid pump 8. Secondary pressure filter inlet pipe 9. Secondary pressure filter The filter inlet mud valve 10 and the mud inlet pump 12 are composed; the mud inlet branch pipe 3 is composed of 5 pipes, and the 5 pipes are arranged parallel to each other, and the cross-sectional positions of the 4 pipes form four vertices of a square, and the remaining one The section of the pipe is located at the geometric center of the square; the filter plate of the plate-and-frame filter press 4 is a square with five mud inlet holes 11, one of which is located at the geometric center of the filter plate, and the other four A mud inlet hole 11 is located at the middle point of the four vertices of the filter plate and the geometric center point; the 5 pipes of the mud inlet branch pipe 3 and the 5 mud inlet holes on the filter plate of the plate and frame filter press 4 The positions of 11 are in one-to-one correspondence; the sum of the areas of the five mud inlet holes 11 is equal to 10% of the area of the surface where the mud inlet holes 11 are located in the filter plate of the plate and frame filter press 4

The mud inlet pump 12 is connected to one end of the mud inlet valve 1 of the first-stage filter press, the other end of the mud inlet valve 1 of the first-stage filter press is connected to the mud inlet main pipe 2, and the other end of the mud inlet main pipe 2 is connected to the 5 ends of the mud inlet branch pipe 3 respectively. The root canals are connected, and the other ends of the five pipes of the mud inlet branch pipe 3 communicate with the five mud inlet holes 11 on the filter plate of the plate and frame filter press 4 one by one. The screw conveyor 5 is located at the bottom of the plate and frame filter press 4 Directly below, the discharge port of the screw conveyor 5 is connected with the feed port of the mixing crusher 6, and the discharge port of the mixing crusher 6 is connected with the mud inlet pipe 9 of the secondary filter press, and the mud inlet pipe 9 of the secondary filter press The other end is connected to a secondary pressure filter mud inlet valve 10, and the other end of the secondary pressure filter mud inlet valve 10 is connected to the mud inlet main pipe 2 between the primary filter pressure mud inlet valve 1 and the mud inlet branch pipe 3. A plunger pump or a solid pump 8 is arranged on the mud inlet pipe 9 of the filter press, and the medicine outlet of the quicklime dosing pipe 7 communicates with the medicine inlet of the mixing crusher 6 .

The method of using the sewage sludge multi-stage coupling plate and frame filter press dewatering device based on multi-point mud feeding in this test is shown in Figures 1, 2 and 3. The specific steps are as follows:

The sludge to be treated is first concentrated by gravity for 16 hours. After concentration, the moisture content of the sludge is 97.8%. Then polyaluminum chloride (PAC) is added to condition the sludge. The dosage of PAC is 0.06g/gSS.

1. First-stage filter press: open the first-stage filter press mud inlet valve 1, close the second-stage filter press mud inlet valve 10, start the mud inlet pump 12, and pass the concentrated and conditioned sludge to be treated in sequence under low pressure conditions. The mud inlet main pipe 2, the mud inlet branch pipe 3 and the five mud inlet holes 11 on the filter plate of the plate and frame filter press 4 are transported into the plate and frame filter press 4. When the sludge stops entering the plate and frame filter press 4, Increase the pressure of the mud inlet pump 12, and continue to transport the sludge to be treated into the plate and frame filter press 4 for dehydration under high pressure conditions. When the plate and frame filter press 4 stops draining, close the first stage filter press mud inlet valve 2 and the mud inlet pump 12, and then perform tympanic membrane pressure filtration on the diaphragm plate in the filter plate of the plate and frame filter press 4, and stop the tympanic membrane pressure filtration when the mud cake formed after the pressure filtration is hardened, and complete the first stage filter press;

The described low pressure condition is that the mud inlet pressure is 0.5MPa; the described high pressure condition is that the mud inlet pressure is 1.0MPa; the pressure of the tympanic membrane filter press is 1.2MPa;

The average moisture content of the mud cake after the first stage of pressure filtration is 81.6%, of which the moisture content of the central layer of the mud cake is 83.5%, and the moisture content of the outer layer of the mud cake is 79.7%;

2. Mixing and crushing: After the first stage of pressure filtration, the plate and frame filter press 4 is opened, and the mud cake formed after the pressure filtration falls into the screw conveyor 5, and is transported to the mixing crusher 6, and the quicklime is fed through the quicklime The drug pipe 7 is added to the mixing crusher 6 and mixed with the mud cake until the plunger pump or the solid pump 8 can make the mixed and crushed sludge enter the mud pipe 9 of the secondary pressure filter; the dosage of quicklime 0.01g/gSS;

3. Second-stage filter press: Open the second-stage filter press mud inlet valve 10 and the plunger pump or solid pump 8, and the sludge mixed and crushed by the mixing crusher 6 passes through the second-stage filter press mud inlet pipe 9 and mud inlet in turn. The main pipe 2, the mud inlet branch pipe 3 and the five mud inlet holes 11 on the filter plate of the plate and frame filter press 4 are transported into the plate and frame filter press 4, and when the sludge stops entering the plate and frame filter press 4, close Second stage filter press mud inlet valve 10 and plunger pump or solid pump 8, and then perform tympanic membrane pressure filtration on the diaphragm plate in the filter plate of plate and frame filter press 4 until the plate and frame filter press 4 stops draining. For pressure filtration, the mud cake in the plate and frame filter press 4 is blown back with dry gas for 5 minutes to remove the moisture on the surface of the mud cake, that is, the dehydration process is completed; the pressure of the tympanic filter press is 1.6MP.

The crushing method of the mixing breaker 6 is stirring; the filter plate includes a diaphragm plate, a matching plate and an anti-corrosion plate; the blowing described in step 1 is done by a blower; the blowing described in step 3 is done by Air blower; the gas in the drying gas described in step 3 is air.

The filter area of the plate and frame filter press used in this test is 1.5m ² , the number of filter plates is 17 (8 diaphragm plates, 7 matching plates and 2 anti-corrosion plates), the size of the filter plate is 250mm×250mm, and the thickness of the filter plate is 15mm , The effective volume of the filter chamber is 12.5L.

The average moisture content of the mud cake after dehydration in this test is 55.2%, and the maximum moisture content difference between the mud cake center layer and the mud cake outer layer (longitudinal) is 0.8%, and the maximum moisture content difference at different positions in the mud cake plane direction is 0.3 %.

Test 2: This test is a comparative test:

On the plate and frame filter press of the same specification, the same raw sludge is used, after the same concentration and conditioning, the sludge is pressed by the traditional plate and frame filter press method through the central point single point mud feeding method. Under the same pressure filtration operation mode, pressure and time of filtration, that is, under the condition of 0.5MPa, low-pressure mud feeding, under the condition of 1.0MPa, high-pressure mud feeding and pressure filtration, under the condition of 1.2MPa After the first tympanic filter press, the plate and frame filter press does not unload the mud, and directly performs the second tympanic filter under the condition of 1.6MPa, and the mud cake is blown back for 5 minutes after the filter press.

Under the conditions of Test 2, the average moisture content of the mud cake obtained by dehydrating the sludge by using the traditional plate-and-frame filter press method was 61.7%;

Among them, the moisture content of the central layer of the mud cake near the central mud entry point is 62.4%, the moisture content of the outer layer of the mud cake near the central mud entry point is 59.4%, and the central layer of the mud cake and the outer layer of the mud cake (longitudinal) contain water The rate difference is 3%;

The moisture content of the central layer of the mud cake far away from the central mud entry point is 63.7%, the moisture content of the outer layer of the mud cake far away from the central mud entry point is 61.3%, and the difference in moisture content between different positions in the mud cake plane direction is 2.4%.

The analysis shows that, compared with the traditional plate and frame filter press method in Test 2, the multi-stage coupled plate and frame filter press dehydration method based on multi-point mud feeding in Test 1 was used under the same operating conditions and energy consumption. The average moisture content of the rear mud cake is reduced by 6.5%, and the uneven distribution of moisture content in the surface direction and longitudinal direction of the mud cake is greatly reduced.

Claims (8)

1. A multi-stage coupling plate and frame filter press dewatering device for sewage sludge based on multi-point mud entry, characterized in that the multi-stage coupling plate and frame filter press dewatering device for sewage sludge based on multi-point mud entry is composed of a first-stage filter press Mud inlet valve (1), mud inlet main pipe (2), mud inlet branch pipe (3), plate and frame filter press (4), screw conveyor (5), mixing crusher (6), quicklime dosing pipe (7 ), a plunger pump or a solid pump (8), a secondary pressure filter inlet pipe (9), a secondary pressure filter inlet valve (10) and a mud inlet pump (12); the described mud inlet branch pipe (3 ) consists of 5 tubes, the 5 tubes are arranged parallel to each other, the cross-sectional positions of the 4 tubes form the four vertices of a square, and the cross-section of the remaining tube is located at the geometric center of the square; the plate and frame filter press (4) The filter plate is a square with 5 mud inlet holes (11) above, wherein one mud inlet hole (11) is located at the geometric center point of the filter plate, and the other four mud inlet holes (11) are located on the four sides of the filter plate The middle point of a vertex and the geometric center point; 5 pipes of the described mud inlet branch pipe (3) and 5 mud inlet holes (11) on the filter plate of the plate and frame filter press (4) one-to-one correspondence; The mud inlet pump (12) is connected to one end of the mud inlet valve (1) of the first-stage filter press, and the other end of the mud inlet valve (1) of the first-stage filter press is connected to the mud inlet main pipe (2). The other end is connected with 5 pipes of the mud inlet branch pipe (3) respectively, and the other end of the 5 pipes of the mud inlet branch pipe (3) is connected with 5 mud inlet holes (11) on the filter plate of the plate and frame filter press (4). ) are connected in one-to-one correspondence, the screw conveyor (5) is located directly below the plate and frame filter press (4), and the discharge port of the screw conveyor (5) is connected with the feed port of the mixing crusher (6), and the mixing and crushing The discharge port of the device (6) is connected with the secondary pressure filter inlet pipe (9), and the other end of the secondary pressure filter inlet pipe (9) is connected with a secondary pressure filter inlet valve (10). The other end of the filter inlet mud valve (10) is connected to the mud inlet main pipe (2) between the first stage filter press mud inlet valve (1) and the mud inlet branch pipe (3), and the second stage filter press mud inlet pipe (9) A plunger pump or a solid pump (8) is arranged on the top, and the drug outlet of the quicklime dosing pipe (7) is communicated with the drug inlet of the mixing breaker (6). 2. A sewage sludge multi-stage coupling plate and frame filter press dewatering device based on multi-point mud feeding according to claim 1, characterized in that the crushing method of the mixing breaker (6) is stirring or impacting. 3. A sewage sludge multi-stage coupling plate and frame filter press dewatering device based on multi-point mud feeding according to claim 1, characterized in that the filter plate includes a diaphragm plate, a matching plate and an anti-corrosion plate. 4. The multi-stage coupling plate and frame filter press dewatering device for sewage sludge based on multi-point mud feeding according to claim 1, characterized in that the sum of the areas of the five mud inlet holes (11) is less than or equal to the plate and frame filter press 20% of the area of the surface where the mud inlet hole (11) is located in the filter plate of the filter press (4), and greater than or equal to 5% of the area of the surface where the mud inlet hole (11) is located in the filter plate of the plate and frame filter press (4) . 5. A method for using a sewage sludge multi-stage coupling plate and frame filter press dewatering device based on multi-point mud entry as claimed in claim 1, characterized in that the sewage sludge multi-stage coupling plate and frame based on multi-point mud entry The method of using the filter press dehydration device is as follows: 1. First-stage filter press: open the first-stage filter press mud inlet valve (1), close the second-stage filter press mud inlet valve (10), start the mud inlet pump (12), and discharge the sludge to be treated under low pressure conditions The mud is fed into the plate and frame filter press (4) through the mud inlet main pipe (2), the mud inlet branch pipe (3) and the five mud inlet holes (11) on the filter plate of the plate and frame filter press (4) in turn. When the sludge stops entering the plate and frame filter press (4), increase the pressure of the sludge inlet pump (12), and continue to transport the sludge to be treated into the plate and frame filter press (4) for dehydration under high pressure conditions. When the plate and frame filter press (4) stops draining, close the primary filter press mud inlet valve (2) and mud inlet pump (12), and then inflate the diaphragm plate in the filter plate of the plate and frame filter press (4) Perform tympanic membrane pressure filtration, stop tympanic membrane pressure filtration when the mud cake formed after pressure filtration appears compaction, and complete the first stage of pressure filtration; The low pressure condition is that the mud inlet pressure is 0.4MPa～0.8MPa; the high pressure condition is that the mud inlet pressure is 1.0MPa～1.4MPa; the pressure of the tympanic membrane filter is 1.2MPa～1.6MPa; 2. Mixing and crushing: After the first stage of filtration, open the plate and frame filter press (4), and the mud cake formed after the filtration will fall into the screw conveyor (5) and be transported to the mixing crusher (6) , add quicklime to the mixing crusher (6) through the quicklime dosing pipe (7) and mix with the mud cake and crush it to the plunger pump or solid pump (8) so that the mixed and crushed sludge can enter the secondary press filter Into the mud pipe (9); the dosage of quicklime is 0.01g/gSS～0.05g/gSS; 3. Second-stage filter press: open the second-stage filter press mud inlet valve (10) and plunger pump or solid pump (8), and the sludge mixed and crushed by the mixing crusher (6) will pass through the second-stage press filter in turn. Five mud inlet holes (11) on the filter plate of the mud pipe (9), the mud inlet main pipe (2), the mud inlet branch pipe (3) and the plate and frame filter press (4) are transported into the plate and frame filter press ( In 4), when the sludge stops entering the plate and frame filter press (4), close the secondary filter press mud inlet valve (10) and the plunger pump or solid pump (8), and then the plate and frame filter press (4) ) diaphragm plate in the filter plate is blown to perform tympanic membrane pressure filtration until the plate and frame filter press (4) stops drainage, and dry gas or hot gas is used to filter the mud cake in the plate and frame filter press (4) The dehydration process is completed by backflushing for 5 minutes to remove the moisture on the surface of the mud cake; the pressure of the tympanic filter press is 1.6MPa-2.0MPa. 6. A method for using a sewage sludge multi-stage coupling plate and frame filter press dewatering device based on multi-point mud feeding according to claim 4, characterized in that the blowing described in step 1 is through a blower or an air compressor Completed. 7. A method for using a sewage sludge multi-stage coupling plate and frame filter press dewatering device based on multi-point mud feeding according to claim 4, characterized in that the blowing described in step 3 is through a blower or an air compressor Completed. 8. A method for using a sewage sludge multi-stage coupling plate and frame filter press dehydration device based on multi-point mud feeding according to claim 4, characterized in that the gas in the dry gas and hot gas described in step 3 air, carbon dioxide or nitrogen.